Waterproofing Membrane

ABSTRACT

Disclosed is a waterproofing membrane that comprises a carrier sheet, a pressure sensitive adhesive layer on one surface of the carrier sheet, and a protective coating layer on the adhesive layer. The protective coating layer comprises a highly reflective protective coating layer operative to bond to concrete cast against it, particularly one that is produced from an aqueous coating comprising an acrylic emulsion, a filler, and a white pigment. The pigment volume concentration of the filler plus white pigment is greater than or equal to 55% by volume. The protective coating layer protects the membrane against weather exposure, tolerates foot traffic and strongly adheres to concrete cast against it. Also disclosed is a waterproofing membrane comprising a carrier sheet, a pressure sensitive adhesive layer, a protective coating layer, and a highly releasable bonding layer. The preferred highly releasable bonding layer comprises nanoscale silica and a binder.

FIELD OF THE INVENTION

The present invention relates to a pre-applied waterproofing membranethat will adhere to concrete applied against its surface.

BACKGROUND OF THE INVENTION

Sheet-like waterproofing membrane laminates are well-known forapplication to concrete and other substrates. These laminates typicallycomprise a carrier sheet and a pressure sensitive adhesive layer. Inmany applications, the waterproofing sheet material is applied to aconcrete substrate that has already been formed, such as a buildingfoundation. In such a case, the adhesive layer of the membrane isapplied against the cured concrete surface. In another technique, thewaterproofing membrane is affixed to the concrete form or lagging withthe carrier sheet against the lagging and the adhesive portion facingtoward the cavity in which the concrete is poured. The adhesive portionof the membrane will adhere to the freshly poured concrete, thusproviding a fully adhered waterproofing membrane on the cured concretesurface after the lagging is removed. This technique is sometimesreferred to as “blind side” (or pre-applied) waterproofing. A similarprocess may be used on horizontal surfaces where the membrane is appliedto compacted soil or gravel or to a concrete slab, with the adhesiveportion facing upward, then casting concrete against the membrane.

In addition to the carrier sheet and pressure sensitive adhesive layer,typical commercial waterproofing membranes include a removable releasesheet that is used to prevent the adhesive portion of the membrane fromadhering to the carrier sheet or other portion of the membrane when themembrane is rolled up. This release sheet must be removed from themembrane prior to or during installation and disposed in the trash, thuscreating environmental waste.

U.S. Pat. No. 3,900,102 (Hurst) discloses one such membrane comprising apolyethylene support sheet, a bituminous adhesive and a releasablesiliconized paper for protecting the adhesive. The release paper isremoved as the membrane is unrolled and adhered to a building substrate(see Hurst FIG. 4). U.S. Pat. No. 4,751,122 (May) discloses a membranelaminate that includes a sheet-like paper substrate with a releasecoating (e.g., silicone) on one face and a waterproofing pressuresensitive adhesive on the other face. This membrane also includes aremovable strip along the edge which, when removed, permits overlappingseams to adhere. U.S. Pat. No. 4,172,830 (Rosenberg) and U.S. Pat. No.4,215,160 (Rosenberg) disclose paperless membrane laminates that includea silicone release coating on the outer surface of the carrier sheet toprevent the adhesive layer from adhering to the carrier sheet when themembrane is rolled up. U.S. Pat. No. 5,254,661 (Wilson) discloses asimilar type of paperless membrane laminate in which the release coatingis a water-based silicone emulsion. During installation, edge portionsof the release coating may be removed by wet abrasion to permit adhesionof overlap seams of adjacent membranes.

U.S. Pat. No. 4,994,328 (Cogliano) discloses a waterproofing membranecapable of adhering to freshly poured concrete (i.e., blind-side orpre-applied waterproofing). The membrane has a bituminous adhesive layerthat is coated with a non-tacky, water-insoluble polymeric coating suchas, for example, a polyvinyl alcohol, silica, and glycerin mixture in aweight ratio of 1:10:0.5. The coating purportedly protects the adhesivelayer while permitting a strong adhesive bond to freshly pouredconcrete. However, the coating can be slippery when wet and, thus, notsuitable for foot traffic. U.S. Pat. No. 5,316,848 (Bartlett) disclosesa similar blind-side waterproofing membrane that includes a carrierlayer, a pressure sensitive adhesive layer, and a protective coating onthe adhesive layer, wherein the coating may be selected from varioustypes of polymers, preferably an acrylic-based elastomer, such asstyrene butyl acrylate. U.S. Pat. No. 5,496,615 (Bartlett) discloses asimilar membrane laminate where the protective coating has a finelydivided particulate material, such as sand, calcium carbonate, cement,titanium dioxide, etc., dusted thereon. The Bartlett patents suggest itis preferred that the protective coating is elastomeric (meaning it willstretch to at least twice its original length and return toapproximately its original length), has a penetration greater than 30dmm, and includes carbon black. The exemplified Bartlett membranesexhibit poor bond to concrete after exposure to LTV radiation.

U.S. Pat. No. 6,500,520 (Wiercinski) discloses a membrane laminatehaving a carrier support sheet, an adhesive layer, and embedded on theadhesive layer a layer of granulated inorganic particulates capable ofreacting with concrete, such as aluminum oxide trihydrate, silicadioxide, fly ash, blast furnace slag, alkali or alkaline earth metalsalts, etc. The particles may be attached to the adhesive layer using awater-soluble material such as ethylene vinyl acetate or polyvinylalcohol.

Typical commercial waterproofing membranes used for blind-side (orpre-applied) applications include a release sheet and unroll wrong sideup with the adhesive portion facing downward. This forces the installerto first unroll then flip over a large, unwieldy membrane prior toinstalling it. Alternatively, two installers are needed to lift theheavy roll so that it may be unrolled with the correct side facingupward. The need to remove and dispose of a release liner requiresadditional labor and creates a considerable amount of trash, thedisposal of which has significant monetary and environmental costs.

It would be advantageous to provide a waterproofing membrane that bindsstrongly to concrete cast against its surface, particularly afterexposure to sunlight. In addition, it would be advantageous to provide awaterproofing membrane that has an outer surface that will easilytolerate foot traffic, that is not tacky, and that does not wash off,blister or delaminate when exposed to water (i.e., good immersionresistance). It would also be advantageous to provide a waterproofingmembrane that has good blocking resistance (i.e., one surface does notadhere to the other surface) so that it does not require a release sheetthat must be removed and disposed of at the job site. In addition, itwould be advantageous to provide a waterproofing membrane that is rightside up (i.e., carrier sheet facing down and adhesive/protective coatingfacing up) when it is unrolled at the job site. Also, it would beadvantageous to provide a waterproofing membrane with an outer layerthat is sufficiently hard (lower tack) for good trafficability, yetsufficiently flexible that it will not crack

SUMMARY OF THE INVENTION

The present invention embraces a waterproofing membrane in the form of asheet-like laminate that comprises a carrier sheet, a pressure sensitiveadhesive layer on one surface of the carrier sheet, and a protectivecoating layer on the adhesive layer. The protective coating layer ishighly reflective and operative to bond to concrete cast against it. Ithas a penetration ≦20 dmm (ASTM D5) and a reflectivity ≧55%, measured bya reflectometer perpendicular to a surface illuminated at a 45° angle.It comprises an acrylic or methacrylic polymer having at least 50 wt %acrylic or methacrylic monomer units and a Tg of −40° C. to 0° C. Itfurther includes a filler and a white pigment, wherein the pigmentvolume concentration (PVC) of the filler plus white pigment is greaterthan or equal to 55% by volume. The protective coating layer is producedfrom an aqueous coating comprising an acrylic emulsion, a filler, and awhite pigment.

A preferred embodiment of the invention is a waterproofing membranecomprising a carrier sheet, a pressure sensitive adhesive layer, aprotective coating layer, and a highly releasable bonding layer. Thepreferred highly releasable bonding layer comprises nanoscale silica anda binder.

Although the waterproofing membrane may optionally include a removablerelease sheet, if desired, it is preferred that the membrane does notinclude a release sheet. The protective coating layer protects themembrane against weather exposure, tolerates foot traffic and stronglyadheres to concrete cast against it. The waterproofing membranes of thepresent invention have a protective coating layer that contains a highlevel of filler and white pigment, thus resulting in a high PVC, highreflectivity, low penetration, low tack, good trafficability, good bondto concrete after UV exposure, good blocking resistance and goodimmersion resistance.

The present invention also embraces a method of waterproofing a concretestructure by applying a waterproofing membrane as defined herein to abuilding substrate or concrete form with the protective coating layer ofthe membrane facing the area into which the concrete will be cast, andcasting concrete such that it contacts the protective coating layer ofthe membrane.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a cross-section of a waterproofing membrane of thepresent invention having three layers.

FIG. 2 depicts a cross-section of a preferred waterproofing membrane ofthe present invention having four layers.

FIG. 3 depicts examples of various texturing patterns that may beapplied to the surface of the protective coating layer in an embodimentof the present invention.

FIG. 4 depicts a cross-section of a preferred waterproofing membrane ofthe present invention having a protective coating layer with a texturedpattern, wherein two membrane surfaces are in contact as in a roll.

DETAILED DESCRIPTION OF THE INVENTION

One embodiment of the waterproofing membrane of the present invention isdepicted in FIG. 1, which shows a cross-section of the membrane takenalong the width of the membrane. Typical commercial membranes are in theform of a sheet-like laminate with a width in the range of about 30 to185 cm, more typically about 60 to 140 cm, preferably about 80 to 130cm, and a length of about 5 to 60 m, more typically about 15 to 36 m,and are rolled up into a roll. These membranes generally have athickness of about 0.15 mm to about 5 mm, more typically about 0.25 mmto about 2.5 mm, preferably about 0.25 mm to about 1.8 mm.

As shown in FIG. 1, the waterproofing membrane comprises at least threelaminated layers. The first layer is a carrier sheet 2 and the secondlayer is an adhesive layer 4, which is adhered to one surface (i.e., afirst surface) of the carrier sheet. The third layer of thewaterproofing membrane is a protective coating layer 6 on the adhesivelayer 4. Optionally, the waterproofing membrane may include a removablerelease sheet (not shown) on the protective coating layer 6. Asdepicted, the protective coating layer 6 is on the side of the adhesivelayer 4 that is opposite the side of the adhesive layer that is adheredto the carrier sheet 2. The waterproofing membrane may optionallyinclude additional layers of material on either face of the carriersheet as desired. For example, a second adhesive layer may be adhered tothe other surface (i.e., a second surface opposite the first surface) ofthe carrier sheet (e.g., to enable the membrane to be adhered to asubstrate). The adhesive layer 4 is adhered either directly onto asurface of the carrier sheet, or indirectly if there is an optionaladditional layer of material interposed between the carrier sheet 2 andthe adhesive layer 4. Preferably, the protective coating layer 6 willinclude on its outer surface a highly releasable bonding layer 7, asshown in FIG. 2.

The carrier sheet 2 provides mechanical strength and waterproofingintegrity for the membrane. The carrier sheet typically will have athickness of about 0.05 to 2.0 mm, preferably about 0.3 to 1.0 mm, andshould comprise a generally smooth surface, such as is provided byfilms, sheets, fabrics, and extrusion coated woven and non-wovenfabrics. Suitable materials for films and extrusion coatings includepolypropylene, polyethylene, ethylene-propylene copolymers,ethylene-olefin copolymers, ethylene-vinyl acetate copolymers, polyvinylacetate, polyethyl acrylate, polytetrafluoroethylene (PTFE),polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET),polyvinyl chloride (PVC), polyamides and combinations thereof.Polyethylene and polypropylene are preferred. A preferred carrier sheetcomprises a thermoplastic film of high density polyethylene (HDPE).Fabrics may be woven or non-woven and may comprise polyethylene,polypropylene, polyethylene terephthalate and polyamide. A wovenpolypropylene fabric is particularly suitable.

Generally, the carrier sheet is not surface treated to increase thesurface tension. However, in some cases it may be desirable to treat thesurface of the carrier sheet on which the adhesive will be applied inorder to enhance adhesion of the adhesive to the carrier sheet. One suchsurface treatment option is corona treatment. Preferably, the carriersheet will not be corona treated, particularly the surface of thecarrier sheet that comes in contact with the protective coating layer 6or the releasable bonding layer 7 (when the membrane is rolled up).Generally, it is preferred that the face of the carrier sheet thatcontacts the protective layer 6 or the highly releasable bonding layer 7have a surface tension of 40 dynes/cm or less, preferably 35 dynes/cm orless.

Additives may be incorporated into the carrier material to reducesurface tension. These may be incorporated into the bulk of the materialin a separate compounding step. The additives may also be incorporatedinto the bulk of the material during the melt extrusion process toproduce a sheet, film, or extrusion coated fabric.

The adhesive layer 4 may comprise a non-bituminous pressure sensitiveadhesive or a rubber modified bitumen pressure sensitive adhesive. Theadhesive layer typically will have a thickness of about 0.05 to 2.5 mm,preferably about 0.07 to 2.0 mm, more preferably about 0.1 to 1.0 mm,most preferably about 0.13 to 0.8 mm.

Suitable non-bituminous, or synthetic, pressure sensitive adhesivesinclude butyl rubber based adhesives, polyisobutylene based adhesives,butyl based adhesives, acrylic based adhesives, vinyl ether basedadhesives, styrene-isoprene-styrene (SIS) based adhesives,styrene-ethylene-butylene-styrene (SEBS) based adhesives,styrene-butadiene-styrene (SBS) based adhesives, styrene-butadienerubber (SBR) based adhesives, and combinations thereof. Preferably, thesynthetic adhesive is a pressure sensitive hot melt adhesive blockcopolymer of SIS, SBS or SEBS, most preferably SIS block copolymer. Fora more detailed description of pressure sensitive adhesives, see Satas,Handbook Of Pressure Sensitive Adhesive Technology, by Van NostrandReinhold Company, Inc. (1982), incorporated herein by reference. Otherrubbers include polyisoprene, polybutadiene, natural rubber,polychloroprene rubber, ethylene-propylene rubber, ethylene alphaolefin, nitrile rubbers, and acrylic rubber.

Other suitable non-bituminous synthetic pressure sensitive adhesives maycomprise amorphous polyolefins. Amorphous polyolefin (APO) is defined aspolyolefin with a degree of crystallinity of less than 30% as measuredby differential scanning calorimetry. These polymers can be eitherhomopolymers of propylene or copolymers of propylene with one or moreα-olefin comonomer, such as, for example, ethylene, 1-butene, 1-hexene,1-octene and 1-decene. The APO polymers of the types herein describedabove are commercially available from Eastman Chemical Company,Kingsport, Tenn., under the trade name designation Eastoflex or fromHuntsman Corporation, Houston, Tex., under the trade name designationRextac or from Degussa Corporation, Parsipanny, N.J., under the tradename designation Vestoplast. Like rubber based adhesives, these are alsocombined with a tackifier and plasticizer to produce a pressuresensitive adhesive. See Eastman bulletin “Pressure-Sensitive AdhesivesBased on Amorphous Polyolefin From Eastman Chemical Company”

Hot melt adhesives based on amorphous polyolefins are suitable as well.In comparison to pressure sensitive adhesives these are not tacky andgenerally comprise only APO, tackifier, and polyolefin wax. Refer toEastman brochure “Formulating Hot Melt Adhesives Based on EpolenePolymers.” Hot melt adhesives based on ethylene vinyl acetate are alsosuitable. See “DuPont Elvax for Adhesives, Sealants, and Wax Blends.”

The non-bituminous or synthetic pressure sensitive adhesive canoptionally contain typical additives, such as light absorbers (e.g.,carbon black, benzotriazoles, hydroxyphenyl-triazine, benzophenones,etc.), light stabilizers (e.g., hindered amines), antioxidants (e.g.,hindered phenols), fillers (e.g., calcium carbonate, silica, titaniumdioxide, etc.), plasticizers, rheological additives, and mixturesthereof. Preferred synthetic adhesives contain light absorbers, lightstabilizers, and antioxidants.

A rubber modified bitumen pressure sensitive adhesive may also be used.All of the rubbers listed above (e.g., SIS, SBS, SEBS, SBR, etc.) may beblended with bitumen to produce a pressure sensitive adhesive. Therubber modified bitumen may also typically include a processing oil suchas an aromatic, naphthenic or paraffinic oil. For unfilled adhesives,the wt. % rubber is about 10% to 22%; the wt. % bitumen is about 43% to90%; and the wt. % processing oil is about 0% to 35%. The pressuresensitive adhesive may also comprise an inorganic filler such as silica,calcium carbonate, talc, or clay. If present, the wt. % filler may beabout 0% to 50% of the total.

Generally, for improved adhesion to post cast concrete it is preferredthat the pressure sensitive adhesive has a penetration greater thanabout 30 decimillimeters (dmm) (150 g, 5 sec., 70° F.) as measuredaccording to ASTM D 5-73, incorporated herein by reference.

The protective coating layer 6 has several functions. It protects themembrane against exposure to weather, it tolerates foot traffic, and,most importantly, it operates to bond to concrete cast against it. In apreferred embodiment, it can also prevent the membrane from adhering toitself when the membrane is rolled up, thus making it possible todispense with the need for a release liner. The protective coating layeris highly reflective and operative to bond to concrete cast against it.The protective coating is produced from an aqueous emulsion comprisingan acrylic or methacrylic polymer (or copolymer), a filler and a whitepigment, wherein the pigment volume concentration of the filler pluswhite pigment is greater than or equal to 55% by volume of total solids(dry). Preferably, the protective coating layer (or more correctly thepolymer or copolymer therein) has a Tg of −40° C. to 0° C., apenetration ≦20 dmm (ASTM D5), and a reflectivity ≧55%, measured by areflectometer perpendicular to a surface illuminated at a 45° angle.Preferably, the acrylic or methacrylic polymer (or copolymer) has atleast 50 wt % acrylic or methacrylic monomer units.

Although not preferred, the protective coating layer 6 may optionallyinclude a coating or dusting of finely divided inorganic particulatematerial on its outer exposed surface. The particulate inorganicmaterial serves to protect the adhesive layer 4 and the protectivecoating layer 6 from the elements prior to casting concrete against it.Preferably, it also improves the adhesion to post-cast concrete. Theparticulate inorganic material may include calcium carbonate, sand,silicate sand, cement (including Portland cement, white Portland cement,calcium aluminate cement, calcium sulfoaluminate cement), talc, titaniumdioxide, slate dust, granite dust, clay, fly ash, slag, metakaolinite,alumina trihydrate, hydrated ground cement (including Portland cement,white Portland cement, calcium aluminate cement, calcium sulfoaluminatecement), partially hydrated cement (including Portland cement, whitePortland cement, calcium aluminate cement, calcium sulfoaluminatecement), and mixtures of two or more of these materials. Preferably, theparticulate inorganic material will have an average particle size in therange of about 0.1-1000 μm, and more preferably in the range of about0.2 to 100 μm.

Although not required and not preferred, the waterproofing membrane mayinclude a removable release sheet (not shown) on the protective coatinglayer 6. The release sheet comprises a film or paper that is coated witha release agent, preferably a silicone. The film may comprisepolyethylene, polypropylene, polyethylene terephthalate, or polyamide. Apaper release sheet may also be coated with a polyolefin layer prior tobeing coated on the polyolefin face with a silicone release agent. Thethickness of the release sheet is typically about 0.01-0.13 mm (about0.5-5 mils).

The waterproofing membrane may be manufactured in a continuous webcoating operation with two coating stations. Pressure sensitive adhesiveis applied at one coating station and the protective coating layer isapplied at the second coating station. The pressure sensitive adhesivemay be coated on to the carrier sheet as a hot melt by a coating deviceselected from a list including knife over roll coater, slot die coater,or roll coater. This two layer construction comprising a carrier sheetand the pressure sensitive adhesive may be cooled. Then the protectivecoating layer may be coated (e.g., by hot melt, solvent or emulsion)onto the exposed face of the pressure sensitive adhesive by a coatingdevice selected from the list including knife over roll coater, slot diecoater, or roll coater. The protective coating layer may be coated atthe same width as the pressure sensitive adhesive or alternatively, itmay be coated at a slightly narrower width than the pressure sensitiveadhesive layer, leaving one edge of the pressure sensitive adhesivelayer uncoated. This narrow uncoated area, referred to as selvedge, isoperable to form an adhesive overlap between two adjoining sheets ofmembrane. The exposed pressure sensitive adhesive edge may be laminatedto a silicone coated release strip that, when removed, will form anadhesive overlap between two adjoining sheets of membrane. In the finalstep the membrane is wound into a roll.

As an alternative construction method, any of the methods may be usedthat are described in copending application PCT/US2009/06134, filed onOct. 20, 2009 (now WO 2010/048198), the disclosure of which isincorporated herein by reference.

The protective coating layer is produced from an aqueous emulsioncomprising an acrylic or methacrylic polymer (or copolymer), a filler,and a white pigment. The polymer in the emulsion comprises, aspolymerized units, at least one acrylic or methacrylic monomer, or acombination thereof. Preferably, the polymer comprises, as polymerizedunits, at least 50 wt %, more preferably at least 75 wt %, of theacrylic or methacrylic monomer. Preferably, the polymer emulsion isprepared by polymerizing one or more alkyl acrylates and/or alkylmethacrylates containing 1-18 carbons per alkyl group. Suitable monomersinclude, for example, methyl acrylate, ethyl acrylate, propyl acrylate,isopropyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate,2-ethyl hexyl acrylate, nonyl acrylate, lauryl acrylate, methylmethacrylate, ethyl methacrylate, propyl methacrylate, isopropylmethacrylate, butyl methacrylate, pentyl methacrylate, hexylmethacrylate, 2-ethyl hexyl methacrylate, nonyl methacrylate, laurylmethacrylate, behenyl methacrylate, and the like. “Alkyl”, as usedherein includes straight chain, branched and cyclic alkyl groups.

In one embodiment of the invention, the (meth)acrylic monomer isco-polymerized with at least one different monomer. By (meth)acrylic ismeant herein an acrylic monomer or methacrylic monomer, or combinationthereof. Suitable co-monomers include, for example, alpha olefinicallyunsaturated carboxylic acids containing 3-5 carbons, and esters thereofcontaining 4-20 carbons; mono-unsaturated dicarboxylic acids containing4-8 carbons; nitriles selected from alpha olefinically unsaturatednitriles containing 3-5 carbons; polymerizable ethylenically unsaturatedmono- and di-carboxylic acids containing 3-8 carbons, and esters thereofcontaining 4-20 carbons; vinyl esters of carboxylic acids containing4-22 carbons; a olefins containing 2-12 carbons; styrene and styrenederivatives; and other polyfunctional monomers. Preferred co-monomersinclude styrene, acrylonitrile, and acrylic acid.

The polymer (or copolymer) in the protective coating layer has a glasstransition temperature (Tg) of from −40° C. to 0° C., as calculatedusing the Fox equation (1) (T. G. Fox, Bull. Am. Physics Soc., Volume 1,Issue No. 3, page 123 (1956)). That is, for calculating the Tg of acopolymer of monomers M1 and M2,

l/Tg(calc.)=w(M1)/Tg(M1)+w(M2)/Tg(M2)

wherein

-   -   Tg(calc.) is the glass transition temperature calculated for the        copolymer;    -   w(M1) is the weight fraction of monomer M1 in the copolymer;    -   w(M2) is the weight fraction of monomer M2 in the copolymer;    -   Tg(M1) is the glass transition temperature of the homopolymer of        M1; and    -   Tg(M2) is the glass transition temperature of the homopolymer of        M2, with all temperatures being measured in ° K.

Examples of suitable emulsion binders that are commercially availableinclude Acronal 5400 (BASF) and UCAR 123 (Arkema), both of which arestyrene-acrylic copolymer emulsions.

The protective coating layer provides for good bond to concrete after UVexposure because it is a highly reflective layer that provides for acooler membrane (which minimizes the rate of pressure sensitive adhesivedegradation. Degradation of the pressure sensitive adhesive reduces bondto concrete) when the membrane is exposed to sunlight as opposed to theuse of coatings of low reflectivity which provide for a warmer membranetemperature when the membrane is exposed to sunlight.

Reflectivity is gauged with a reflectometer (NOVO-SHADE 45/0reflectometer), with the test surface illuminated from a 45° angle andthe intensity of scattered light measured at the perpendicular (i.e.0°). Data is recorded on a grey scale where black is 0% and white is100%. Only shading is measured, irrespective of color, and is referredto as whiteness. Reflective coatings of the present invention exhibit avalue that is greater than or equal to 55%. Preferred coatings exhibit avalue that it is greater than 65%.

The protective coating layer comprises inorganic filler and whitepigment. The volume fraction, in the protective coating layer, of fillerplus white pigment as a volume % of total solids is referred to as thepigment volume concentration (PVC) and is 55% to 90%. The preferred PVCis 55% to 75%. A most preferred PVC is 60% to 70%.

Suitable inorganic fillers include calcium carbonate, silica,diatomaceous earth, barytes, magnesium silicates, talc, clay, andalumina trihydrate. White fillers are preferred. Calcium carbonate is apreferred inorganic filler. The average particle size of the filler is 1μm to 50 μm, preferably 3 μm to 25 μm.

White pigments are included to increase the reflectivity of theprotective coating layer. A pigment that efficiently scatters visiblelight, thereby imparting whiteness, brightness and opacity whenincorporated into a coating is preferred. Preferred pigments includetitanium dioxide, antimony oxide, zinc sulfide, and zinc oxide. Anorganic hollow sphere pigment, Ropaque, produced by Rohm and Haas, mayalso be used. Titanium dioxide is most preferred. Titanium dioxide(TiO₂) and other white pigments opacify paint films primarily bydiffusely reflecting light. This reflection occurs because the whitepigment scatters or bends light strongly. If there is enough whitepigment in a paint film, almost all visible light striking it (exceptfor a very small amount absorbed by vehicle or pigment) will bereflected, and the film will appear opaque, white, and bright. Thevolume % of white pigment as a volume % of filler plus white pigment is5% to 30%.

A high PVC provides for good adhesion between the protective layer andthe pressure sensitive adhesive when the membrane is immersed in water.A protective coating formed from an aqueous emulsion with no inorganicmaterial or a low level of inorganic material exhibits poor adhesion tothe pressure sensitive adhesive under immersion conditions. The PVC alsoeffects protective layer flexibility and the ability to easily unroll aroll of membrane that does not comprise a release liner (referred to asblocking resistance). If the PVC is too low the roll of membrane willnot be easily unwound as the bond strength between the protective layerand the backside of the carrier, in roll form, will be high. Flexibilityis enhanced as the PVC is decreased. Flexibility is needed to minimizecracking of the protective coating layer during manufacturing, thermalcycling, and installation. The protective coating layer will be strainedwhen the membrane is unrolled, during installation to form details andoverlaps and as a result of foot traffic during installation.

Resistance to blocking may be enhanced by texturing the protectivelayer. The texturing provides for a lower level of contact between theprotective coating layer and the carrier sheet when the membrane iswound into a roll. The lower level of contact area provides for greaterresistance to blocking then for a smooth surface of the samecomposition. Various texturing patterns may be used, such as those shownin FIG. 3. The lower level of contact between the textured protectivecoating layer 6 and the carrier sheet 2 is illustrated in FIG. 4, whichillustrates two membrane surfaces in contact as in a roll. The texturedprotective coating layer may also exhibit additional flexibility as wellas blocking resistance in comparison to smooth layer.

The protective coating layer may also contain surfactants, thickeners,antioxidants, UV stabilizers, UV absorbers, biocides, defoamer, wettingagents, and/or coalescing agents. Antioxidants and UV absorbers areoperative to protect the coating and the pressure sensitive adhesiveagainst degradation. UV absorbers are selected from a list includingbenzotriazoles, hydroxyphenyl-triazines, and benzophenones. Antioxidantsare selected from a list including hindered amines and hindered phenols.Tinuvin 292 is a preferred antioxidant. Tinuvin DW 400, Tinuvin 1130,Tinuvin 213, and Tinuvin 571 are preferred UV absorbers. The wt % of UVabsorber on total solids is 0.1% to 1%. The wt % of antioxidant on totalsolids is 0.1 to 1%. Thickeners may include water soluble thickeners,alkali soluble thickeners and clay-based thickeners.

The protective coating layer, upon application to the pressure sensitiveadhesive layer, has a dry (solids only) weight that ranges from 10 g/m²to 200 g/m², preferably 25 g/m² to 100 g/m². If the protective coatinglayer is textured, the coating weight is 60 g/m² to 400 g/m², preferably90 g/m² to 300 g/m².

The penetration of the protective coating layer, as measured accordingto ASTM D5 (150 g/5 sec), is less than or equal to 20 dmm.

In a most preferred embodiment, the waterproofing membrane of thepresent invention will include a releasable bonding layer 7, as depictedin FIG. 2. Four different types of materials may be used as the highlyreleasable bonding layer 7. These include water soluble polymers, alkalisoluble polymers, homopolymers or copolymers of polyvinyl acetate, and alayer comprising a binder and a nanoscale silica. The latter two arepreferred. A highly releasable bonding layer comprising a binder andnanoscale silica is most preferred.

In one embodiment, the highly releasable bonding layer 7 is hydrophilicand will generally comprise a water soluble polymer. Suitable watersoluble polymers may include polyvinyl alcohol (PVOH), polyethyleneoxide (PEO), water soluble cellulosic polymers (e.g., hydroxypropylmethyl cellulose, hydroxyethyl cellulose), hydrolyzed maleic anhydridepolymers and copolymers, polyvinylpyrrolidone, sulfonated polystyrene,polysulfoethyl acrylate, poly(2-hydroxyethylacrylate), polyacrylamide,poly(acrylic acid) and alkali metal salts thereof, natural orsynthetically modified polysaccharides, proteins, alginates, xanthangums, and guar gums. Since this highly releasable bonding material ishydrophilic, it may be completely or partially removed by exposure towater (e.g., rainfall) after the membrane is installed, but beforeconcrete is cast against it. However, concrete will strongly adhere toany residual bonding material and/or to the protective coating.

In another embodiment, the highly releasable bonding layer 7 maycomprise an alkali soluble polymer. In accordance with the presentinvention, an alkali soluble polymer is defined as a polymer that isinsoluble or non-swellable below pH 5 and soluble, or at least partiallysoluble or swellable, above pH 8.

An alkali soluble polymer bonds well to concrete. Without being bound byany theory, it is postulated that a proposed mechanism for bondformation between the alkali soluble polymer and concrete can bedescribed as follows. When concrete is cast against the alkali solublepolymer layer it may dissolve, partially dissolve, swell, or partiallyswell. The polymer is rendered soluble or swellable by reaction of thehydrophilic monomers with alkaline species like calcium hydroxide withinthe concrete. Anhydrides and carboxylic acids both react with calciumhydroxide to form calcium carboxylate salts. Phenol will also react withcalcium hydroxide to form a salt. In one of these states the polymerlayer may diffuse or partially diffuse into the concrete. Once theconcrete sets, the polymer layer and membrane are bonded to theconcrete. Alternatively, only the surface (or a thin layer at thesurface) of the alkali soluble polymer layer may be affected by reactionwith calcium hydroxide in the concrete. While these calcium salts may beinsoluble, partially soluble, or swellable, it is believed the saltformation contributes to the bond between the membrane and concrete castand cured against the bonding material surface of the membrane.

The alkali soluble polymer may comprise one or more hydrophilic monomersand one or more hydrophobic monomers. Hydrophilic monomers are selectedfrom a list including maleic anhydride, a combination of maleicanhydride and a mono-ester/monocarboxylic acid, methacrylic acid,acrylic acid, and vinyl phenol. Hydrophobic monomers are selected from alist including acrylic esters, methacrylic esters, styrene, alpha methylstyrene, alkenes, ethylene, propylene, isobutylene, vinyl chloride, andoctadecene.

One type of alkali soluble polymer includes styrene maleic anhydridecopolymers such as those manufactured by Sartomer. The ratio of styreneto maleic anhydride ranges from 1:1 to 8:1. The number average molecularweight ranges from 2000 to 12,000. Most preferred is SMA 3000 with astyrene:maleic anhydride ratio of 3:1.

Another type of alkali soluble polymer includes combinations of styrenemaleic anhydride and mono-ester/monocarboxylic acid such as thosemanufactured by Sartomer. The acid value in milligrams of KOH per gramof polymer ranges from 90 to 300. The number average molecular weightranges from 2000 to 6000. Most preferred are SMA 2625 and SMA 3840.

Another type of alkali soluble polymer includes acrylic acid and styreneand/or alpha-methyl styrene type polymers manufactured by BASF under thetrade name of Joncryl. These include Joncryl 680 and Joncryl 682.

An additional type of alkali soluble polymer includes reaction productsof hydroxypropyl-methyl cellulose such as those manufactured byShin-Etsu under the trade name of AQOAT including AQOAT ASHG. This ishydroxypropyl methylcellulose acetate succinate.

Another type of alkali soluble polymer includes copolymers ofmethacrylic acid and methylmethacrylate such as those manufactured byEvonik under the trade name EUDRAGIT®. Most preferred is EUDRAGIT® S100.

Another type of alkali soluble polymer includes acrylic acid-ethylacrylate-methyl methacrylate copolymer such as that manufactured byLubrizol under the trade name Avalure. Most preferred is Avalure 315. Afurther type of preferred alkali soluble polymer is a copolymer ofmethylmethacrylate, ethyl methacrylate and acrylic acid. This iscommercially available from Lubrizol as Carboset 526. An additional typeof preferred alkali soluble polymer is a copolymer of ethyl acrylate,methylmethacrylate, and acrylic acid. This is commercially availablefrom Lubrizol as Carboset 525.

Another example of an alkali soluble polymer is a rosin acid. Yetanother example of an alkali soluble polymer is a phenolic resin, suchas a condensation product of phenol and formaldehyde. Suitable phenolicresins include phenolic novolac resins such as those manufactured byGeorgia-Pacific. Most preferred is Georgia-Pacific resin CK-2400.

Alkali soluble polymers may be applied to a web in a continuous processas a solution of the alkali soluble polymer in an organic solvent, as asolution in aqueous ammonia, or as an aqueous emulsion. The aqueousemulsion is often referred to as an alkali soluble emulsion or ASE. Atlow pH the polymer is in the form of an aqueous emulsion. At high pH thepolymer dissolves to form an aqueous solution.

In a preferred embodiment, the highly releasable bonding layer comprisesa homopolymer or a copolymer of polyvinyl acetate (PVAc). The preferredpolymer is polyvinyl acetate homopolymer. Solid polyvinyl acetatehomopolymers (100% solids) are available from Wacker Chemie AG andWacker Chemical Corporation under the trade name Vinnapas. The weightaverage molecular weight ranges from 10,000 g per mole to 500,000 g permole, preferably from 20,000 g per mole to 350,000 g per mole.Typically, these will have a glass transition temperature in the rangefrom 33° C. to 44° C. depending on the molecular weight. Generally, thehigher molecular weight polymers have higher glass transitiontemperatures. Other 100% solids polyvinyl acetate homopolymers are alsomanufactured by McGean. Polyvinyl acetate emulsion may be used as well,such as, for example, polyvinyl acetate emulsion produced by Celaneseunder the trade name Dur-O-Set. Polyvinyl acetate emulsions arepreferred as highly releasable bonding layers as these are manufacturedwith aqueous (and not solvent-based) coatings. The coating weight of ahighly releasable bonding layer comprising polyvinyl acetate is 1 g/m²to 15 g/m², preferably 2 g/m² to 10 g/m², more preferably 3 g/m² to 5g/m².

In a more preferred embodiment, the highly releasable bonding layercomprises nanoscale silica and a binder. Preferably, the coating weight(on the membrane surface) of a highly releasable bonding layercomprising nanoscale silica plus binder is 1 g/m² to 15 g/m², preferably2 g/m² to 10 g/m², more preferably 3 g/m² to 6 g/m². The binder mayinclude any of the polymers identified above for use in the releasablebonding layer—i.e., a water soluble polymer, an alkali soluble polymer,or a homopolymer or copolymer of polyvinyl acetate. However, the polymerbinder must be soluble or dispersible in water because an aqueousmixture of the silica dispersion and binder is needed to produce ahighly releasable bonding layer. Preferred binders include aqueousdispersions of hydrophobic polymer emulsions. A preferred aqueouspolymer emulsion binder is an emulsion of polyvinyl acetate homopolymersuch as that produced by Celanese under the trade name Dur-O-Set.

Aqueous nanoscale silica dispersions are sold by W.R. Grace & Co. underthe trade name Ludox. The nanoscale silica particles in LUDOX colloidalsilica are discrete uniform spheres of silica with no porosity ordetectable crystallinity. Most are dispersed in an alkaline medium whichreacts with the silica surface to produce a negative charge. Because ofthe negative charge, the particles repel one another resulting in stableproducts between pH 8-11. Some grades contain silica with speciallymodified surfaces to give broader stability (pH 4-11). During drying,the hydroxyl groups on the surface of the particles condense bysplitting out water to form siloxane bonds (Si—O—Si) resulting incoalescence and interbonding. Particle size ranges from 5 nm(nanometers) to 30 nm. The volume percentage of silica, as a percentageof silica plus polymer binder, is 30% to 70%, preferably 45% to 65%. Itshould be noted that the size of the silica particles is much smallerthan the particle size of polymer particles in commercial aqueousemulsions, where such polymer particles typically may be approximately200 nm (0.2 μm) or more. Without being bound by theory, it is believedthat the ability of the silica particles to coalesce upon drying,combined with the high volume fraction of silica and the difference inparticle size between the silica particles and the polymer particles,produces a releasable bonding layer having a continuous silica phase.Furthermore, it is believed that the silica particles are covalentlybonded to one another to form the continuous network.

The highly releasable bonding layer is produced from an aqueous ornon-aqueous coating composition. Aqueous coatings are preferred. Thecoating is aqueous if the highly releasable bonding layer comprises awater soluble polymer, an aqueous emulsion, or nanoscale silica. Aqueousor non-aqueous coating compositions may be used to produce highlyreleasable bonding layers comprising an alkali soluble polymer, apolyvinyl acetate homopolymer, or a copolymer of polyvinyl acetate.

In a preferred embodiment the highly releasable bonding layer isproduced from an aqueous composition comprising an emulsion of polyvinylacetate. In another preferred embodiment the highly releasable bondinglayer is produced from an aqueous composition comprising an emulsion ofpolyvinyl acetate and an aqueous dispersion of nanoscale silica.

Another embodiment of the invention is a process to manufacture awaterproofing membrane of FIG. 1 with a smooth protective coating layer6 comprising the steps:

apply a mixture comprising emulsion, filler, and pigment, onto a plasticfilm, pass through a heated oven to dry, producing a protective coatinglayer 6 coated onto the plastic film, and wind into a roll;

coat a hot melt pressure sensitive adhesive 4 onto the carrier sheet 2;

unwind the two layer laminate comprising the protective coating layer 6and the plastic film;

laminate the protective coating layer 6 face of the two layer laminateto the pressure sensitive adhesive 4;

remove the plastic film from the protective coating layer 6, leaving theprotective coating layer adhered to the pressure sensitive adhesive 4;

wind the three layer composite comprising the protective coating layer6, pressure sensitive adhesive 4, and carrier sheet 2 into a roll.

Another embodiment of the invention is a process to manufacture awaterproofing membrane of FIG. 1 with a smooth protective coating layer6 comprising the steps:

coat a hot melt pressure sensitive adhesive 4 onto the carrier sheet 2;

optionally cool the carrier sheet 2/adhesive 4 combination;

apply a mixture comprising emulsion, filler, and pigment, onto thepressure sensitive adhesive 4 to form a protective coating layer 6;

dry the protective coating layer by heating in an oven and/or via heatfrom the hot melt coated pressure sensitive adhesive 4 to produceprotective coating layer 6 coated on the pressure sensitive adhesive 4;

wind the membrane comprising protective coating layer 6, pressuresensitive adhesive 4, and carrier sheet 2 into a roll.

All of the steps above may be performed in a single manufacturingoperation. Thus, the carrier sheet 2 is unwound from an unwind stand andthe adhesive layer 4 is applied to the carrier sheet as a hot melt. Ahot melt coater may be a slot die, knife over roll coater or hot meltroll coater. The adhesive coated carrier may then be optionally cooledby contact with a heat exchanger. Optionally, a narrow release layer maybe applied along one edge of the pressure sensitive adhesive layer. Nextan aqueous mixture comprising emulsion, filler, and pigment is coatedonto the pressure sensitive adhesive layer with a coater that may be aslot die coater, knife over roll coater, curtain coater, or roll coater.The aqueous mixture is supplied to the coater via metering pump fromstorage tanks. The protective coating layer is dried in an oven. The 3layer membrane is then wound into rolls of suitable size forapplication.

Another embodiment of the invention is a process to manufacture awaterproofing membrane of FIG. 1 with a smooth protective coating layer6 comprising the steps:

apply a mixture comprising emulsion, filler, and pigment onto thecarrier sheet 2 and dry to form a protective coating layer 6;

coat a hot melt pressure sensitive adhesive 4 on to either side of thecarrier sheet 2 coated with protective coating layer 6;

wind the 3 layer laminate comprising protective coating layer 6,pressure sensitive adhesive 4, and carrier sheet 2 into a roll;

when the roll is unwound the protective coating layer 6 releases fromthe carrier sheet 2 and remains adhered to the pressure sensitiveadhesive 4.

The mixture comprising an acrylic emulsion, filler, and pigment may beapplied with any one of a number of different types of coaters includinga knife over roll coater, a roll coater, or a slot die coater. Thepressure sensitive adhesive may be applied with any one of a number ofdifferent types of coaters including a slot die coater, roll coater, ora knife over roll coater. The pressure sensitive adhesive is generallyapplied at a temperature range between 135° C. and 177° C. (275° F. and350° F.).

Another embodiment of the invention is a process to manufacture awaterproofing membrane of FIG. 1 with a textured protective coatinglayer 6 (as shown in FIGS. 3 and 4) comprising the steps:

apply a mixture comprising emulsion, filler, and pigment onto a texturedplastic film, pass through a heated oven to dry, producing a texturedprotective layer 6 coated onto the textured plastic film, and wind intoa roll;

coat a hot melt pressure sensitive adhesive 4 onto the carrier sheet 2;

unwind the two layer laminate comprising the textured protective coatinglayer 6 and the textured plastic film;

laminate the face of the textured protective coating layer 6 to thepressure sensitive adhesive 4;

remove the textured plastic film, leaving the textured protectivecoating layer 6 on the pressure sensitive adhesive 4;

wind the three layer composite comprising the textured protectivecoating layer 6, pressure sensitive adhesive 4, and carrier sheet 2 intoa roll.

Another embodiment of the invention is a process to manufacture awaterproofing membrane of FIG. 1 with a textured protective coatinglayer 6 (as shown in FIGS. 3 and 4) comprising the steps:

coat a hot melt pressure sensitive adhesive 4 onto the carrier sheet 2;

optionally cool the carrier sheet 2/adhesive 4 combination;

apply a mixture comprising emulsion, filler, and pigment onto thepressure sensitive adhesive 4 in a roll coating process with an engravedroll to produce a textured protective coating layer 6;

dry the coating by heating in an oven to produce a textured protectivecoating layer 6 coated on the pressure sensitive adhesive 4;

wind the three layer composite comprising the textured protectivecoating layer 6, pressure sensitive adhesive 4, and carrier sheet 2 intoa roll.

All of the steps above may be performed in a single manufacturingoperation.

Another embodiment of the invention is a process to manufacture awaterproofing membrane of FIG. 2 comprising the steps:

coat a highly releasable bonding layer 7 to a plastic film and dry;

apply a mixture comprising emulsion, filler, and pigment on to thesurface of highly releasable bonding layer 7, dry to produce protectivecoating layer 6, and wind into a roll;

coat a hot melt pressure sensitive adhesive 4 onto the carrier sheet 2;

unwind the 3 layer laminate comprising the plastic film, highlyreleasable bonding layer 7, and protective coating layer 6;

laminate the face of protective coating layer 6 of the three layerlaminate to the pressure sensitive adhesive 4;

remove the plastic film leaving protective layer 6/highly releasablebonding layer 7 adhered to the pressure sensitive adhesive;

wind the four layer composite comprising highly releasable bonding layer7, protective coating layer 6, pressure sensitive adhesive 4, andcarrier sheet 2 into a roll.

EXAMPLES

The invention may be further illustrated by the following examples,which are not to be construed as limiting the scope of the invention. Inthese examples, the following materials are used:

-   -   Adva 190 is a poly carboxylate dispersant.    -   Acronal S 400 is a styrene butyl acrylate emulsion (BASF).    -   Dur-O-Set 310 is a 55% solids polyvinyl acetate emulsion        (Celanese).    -   Tinuvin 292 is a hindered amine light stabilizer (Ciba-Geigy).    -   Tinuvin 328 is a hydroxyphenylbenzotriazole UV absorber        (Ciba-Geigy).    -   Tinuvin 400 is a hydroxyphenyl-triazine UV absorber        (Ciba-Geigy).    -   Pluronic L81 is an EO/PO surfactant.    -   Kraton 1163 is an SIS block copolymer.    -   Escorez 1310 is a C-5 type tackifier (Exxon).    -   Shellflex 371 is a naphthenic oil.    -   Irganox 1010 is a hindered phenol antioxidant (Ciba-Geigy).    -   Ludox AS 40 is a colloidal silica dispersion where the silica        has an average particle size of 22 nm and the solids level is        40%.

In addition, the following test procedures are used:

Bond to Concrete:

Since waterproofing membranes are normally subject to exposure tosunlight prior to concrete being cast, it is highly desirable that suchmembranes maintain their ability to adhere to concrete after suchexposure. Adhesion of the membranes to concrete is tested by castingconcrete against the outer face (i.e., either the protective coatinglayer or the releasable bonding layer, if present) of 2 in ×6 in (5cm×15 cm) membrane samples, allowing the concrete to cure for sevendays, then measuring peel adhesion with an Instron mechanical tester ata peel angle of 90° and a peel rate of 2 in (5 cm)/min. Bond to concreteis measured for samples not exposed to UV radiation (initial) and forsamples exposed to UV radiation prior to casting concrete, where the UVexposure uses the EMMAQUA accelerated test in which the exposurecorresponds to the equivalent of one month UV exposure (28 mj) or twomonths UV exposure (56 mj).

Blocking Resistance:

Since waterproofing membranes are normally wound into a roll, it ishighly desirable to insure that one surface of the membrane (i.e.,either the protective coating layer or the releasable bonding layer, ifpresent) does not strongly adhere to the other surface of the membrane(i.e., the carrier sheet). Otherwise, it will be difficult to unwind theroll. To test blocking resistance, a layer of 16 mil (0.4 mm) HDPE isplaced on the outer surface (i.e., either the protective coating layeror the releasable bonding layer, if present) of a 2 in ×8 in (5 cm×20cm) membrane sample, a 2 psi (70 g/cm²) load is placed on top, then thisassembly is placed in an oven at 150° F. (66° C.) for 30 days (2 days inthe case of Table 5 samples). After cooling to room temperature, eachsample is tested with a T-peel test using an Instron mechanical testerusing a cross head speed of 10 in (25.4 cm)/min. Blocking is measured aspounds per lineal inch (pli).

Water Immersion:

Since waterproof membranes are normally exposed to weather, such asrain, prior to concrete being cast, it is highly desirable that theprotective coating layer does not wash off or delaminate when exposed towater since this would leave the pressure sensitive adhesive layerexposed. To test adhesion of the protective coating layer to thepressure sensitive adhesive under immersion conditions, samples ofmembrane are immersed in water for 15 days or 30 days, then removed anddried with a paper towel. Adhesion of the protective coating layer (orcombination of protective coating layer/releasable bonding layer) to thepressure sensitive adhesive is tested by application of adhesive tape tothe surface and assessment of peel adhesion by hand. The layers are welladhered when adhesive failure occurs between the adhesive tape and thesurface to which it is adhered.

Membrane preparation. Membranes are prepared using an aqueous basedcoating formulation for a protective coating layer as shown in Table 1.

TABLE 1 Highly Reflective Protective Coating Ingredient Wt. % TiO2 12.95 μm calcium carbonate 51.4 Adva 190 0.5 Acronal S400 18.4 Tinuvin 2920.2 Tinuvin 400 DW 1.6 Water 14.8 Pluronic L 81 0.15 Total 100.0

The coating formulation is prepared in a 1 quart (0.95 l) can with aCowels dissolver. Water and ADVA 190 are mixed at low speed. Whilemixing at 500 RPM, titanium dioxide is added followed by calciumcarbonate. Mixing speed is increased to 2000 RPM and mixing continuedfor five minutes. Mixing speed is reduced to 500 RPM. The Acronalemulsion and all remaining ingredients are added and mixing is continuedfor one more minute.

The coating formulation for the highly releasable bonding layer isprepared by mixing 10 parts Dur-O-Set 310 polyvinyl acetate emulsion and50 parts water, then mixing with 40 parts of Ludox AS40 colloidalsilica.

Two types of membranes are prepared as depicted in FIGS. 1 and 2. Thefirst is a three layer membrane comprising a highly reflectiveprotective coating layer, pressure sensitive adhesive, and carriersheet. The second is a four layer membrane comprising a highlyreleasable bonding layer, a protective coating layer, pressure sensitiveadhesive, and carrier sheet.

To prepare the first membrane, the protective coating layer is coatedonto an untreated 16 mil (0.4 mm) high-density polyethylene (HDPE) sheetwith a drawdown bar. The gap for the drawdown bar is selected to achievethe desired coating weight. The coated sheet is first dried for fiveminutes at room temperature and then dried for 5 minutes in an oven at150° F. (66° C.).

A sheet of 16 mil (0.4 mm) HDPE is coated with 15 mils (0.38 mm) of SISbased pressure sensitive adhesive (see formulation below).

TABLE 2 Kraton 1163 27.3 Escorez 1310-LC 56.5 Shellflex 371 Oil 14.7Irganox 1010 1.0 Tinuvin 328 0.5

This coated sheet is applied to the coated sheet above with the pressuresensitive adhesive in contact with the protective coating layer. Thisfour layer construction comprising HDPE, protective coating layer,pressure sensitive adhesive and HDPE is peeled into two layers, wherebythe protective coating layer releases easily from the HDPE sheet,leaving a three layer structure comprising HDPE sheet, pressuresensitive adhesive and protective coating layer and an uncoated HDPEsheet.

To prepare the second membrane, the highly releasable bonding layer iscoated onto an untreated 16 mil (0.4 mm) HDPE sheet with a drawdown bar.The gap for the drawdown bar is selected to achieve the desired coatingweight. The coated sheet is first dried for five minutes at roomtemperature and then dried for 5 minutes in an oven at 150° F. (66° C.).The protective coating layer is coated onto the dry highly releasablebonding layer with a drawdown bar. The gap for the drawdown bar isselected to achieve the desired coating weight. The coated sheet isfirst dried for five minutes at room temperature and then dried for 5minutes in and oven at 150° F. (66° C.) to produce a three layerlaminate comprising protective coating layer, highly releasable bondinglayer, and HDPE sheet.

A sheet of 16 mil (0.4 mm) HDPE is coated with 15 mils (0.38 mm) of SISbased pressure sensitive adhesive, then this coated sheet is applied tothe three layer laminate described above, with the pressure sensitiveadhesive in contact with the protective coating layer. This five layerconstruction comprising HDPE sheet, pressure sensitive adhesive,protective coating layer, highly releasable bonding layer, and HDPEsheet is peeled into two layers, whereby the highly releasable bondinglayer releases easily from the HDPE sheet leaving a four layer structurecomprising HDPE sheet, pressure sensitive adhesive, protective coatinglayer, and highly releasable bonding layer and an uncoated HDPE sheet.

Seven membranes are prepared with the constructions shown in Table 3.Samples 1 through 6 have three layers as depicted in FIG. 1, whilesample 7 has four layers as depicted in FIG. 2.

TABLE 3 Protective Releasable Sample ctg layer bndg layer Blocking Bondto concrete (pli) No. Wt (g/m²) Wt (g/m²) pli Immersion 0 mj 28 mj 56 mj1 50 NA 0.03 11.6 2 50 NA pass 15 day 11.4 11.3 11.5 3 68 NA 0.04 pass30 day 4 68 NA 0.02/0.065 5 70 NA pass 15 day 10.9 13.3 13.3 6 72 NA 8.97 56 3.5 falls off (0) pass 30 day 6.7

As can be seen from the above data, the membranes of the presentinvention have minimal blocking (adhesion of outer layer to carriersheet) and good bond to concrete, including good bond to concrete afterexposure to UV radiation. In addition, the outer layer does notdelaminate or wash off on exposure to water. Bond to concrete issignificantly improved in comparison to that for the protective coatingsexemplified in U.S. Pat. No. 5,316,848 (Bartlett), where the bond toconcrete dropped to about 1 pli after 40 mj exposure.

Membranes are also prepared to demonstrate the effects of pigment volumeconcentration (PVC) and penetration on blocking resistance. Aqueousbased coating formulations for protective coating layers are shown inTable 4. These coatings are used to prepare three layer membranes asdepicted in FIG. 1 as previously described. The membrane constructionsare delineated in Table 5, along with the PVC, coating weight andpenetration of their respective protective coating layers. Thesemembranes are tested for blocking resistance according to the procedurepreviously described (with two day oven treatment) and those values arealso shown in Table 5.

TABLE 4 Protective Coating C D E F PVC 68.7 62.5 52.9 36.2 TiO₂ 10.3 9.78.7 6.6 5 μm CaCO₃ 53.7 50.5 45.1 34.1 Adva 190 0.5 0.4 0.4 0.3 AcronalS400 19.0 23.8 31.9 48.3 Pluronic L 81 0.2 0.2 0.1 0.2 Water 16.3 15.413.7 10.5 Total 100.0 100.0 100.0 100.0

TABLE 5 Coating Coating Sample Protective PVC Wt 2 day Penetration No.Coating (%) (g/m²) Blocking (pli) (dmm) 8 C 68.7 75 falls off (0) 3 9 C68.7 59 falls off (0) 10 D 62.5 76 0.05 7.3 11 D 62.5 52 0.1 12 E 52.970 slip stick (1.0 pli 27.3 peaks) 13 E 52.9 47 slip stick (1.5 plipeaks) 14 F 36.2 57 slip stick (2.0 pli 44 peaks) 15 F 36.2 42 slipstick (2.5 pli peaks)

As can be seen from the above data, blocking resistance is good (peeladhesion values are low) for samples made with high PVC coatings (68.7and 62.5). These high PVC samples also had low penetration of less than20 dmm. At lower PVC (and higher penetration), blocking resistancebecomes poor with samples exhibiting slip stick behavior, which is analternation between brittle (as for higher PVC samples) and adhesivefailure (1-2.5 pli).

Blocking resistance was also evaluated for compositions described inU.S. Pat. No. 5,316,848 and U.S. Pat. No. 5,496,615. Membranes like thatdepicted in FIG. 1 comprising protective coating layer, pressuresensitive adhesive, and carrier sheet are prepared as described above.In one sample, the outer layer comprises only UCAR 123 at 70 g/m². In asecond sample, the outer layer comprises UCAR 123, onto the surface ofwhich is dusted calcium carbonate. Blocking resistance is tested aspreviously described, except with a 10 day oven treatment. The firstsample had a peel value of 5 pli and the second sample had a peel valueof 1.9 pli. Such high values mean that both membranes will require arelease sheet if they are to be wound into a roll.

The water immersion test was also conducted on membranes comprising nofiller in the protective coating layer. All membranes comprise 16 mil(0.4 mm) HDPE sheet, 15 mils (0.38 mm) of pressure sensitive adhesive,and approximately 70 g/m² of polymeric protective coating comprising nofiller. See table 7. For all of these samples, significantblistering/delamination of the protective coating layer from thepressure sensitive adhesive occurs after one to three days immersion.

TABLE 7 Emulsion Polymer Type Tg (° C.) Acronal S400 acrylic/styrene −6Airflex EF500 vinyl acetate/ethylene 5 Airflex 7200 vinylacetate/ethylene 0 Flexbond 381 vinyl acetate/acrylic 13 Flexbond 325vinyl acetate/acrylic 19 Airflex 400 vinyl acetate/ethylene 0 UCAR 357vinyl acetate/acrylic 23 Rhoplex 2438 acrylic −22 UCAR 123acrylic/styrene −17

1. A waterproofing membrane in the form of a sheet-like laminatecomprising a carrier sheet, a pressure sensitive adhesive layer on onesurface of the carrier sheet, and a protective coating layer on theadhesive layer, wherein the protective coating layer has a penetration≦20 dmm (ASTM D5), and a reflectivity ≧55%, measured by a reflectometerperpendicular to a surface illuminated at a 45° angle, and wherein theprotective coating layer comprises an acrylic or methacrylic polymerhaving at least 50 wt % acrylic or methacrylic monomer units and a Tg of−40° C. to 0° C., a filler and a white pigment, wherein the pigmentvolume concentration of the filler plus white pigment is 55% to 90% byvolume.
 2. The waterproofing membrane according to claim 1 wherein theprotective coating layer is produced from an aqueous emulsion coatingcomprising an acrylic or methacrylic polymer having at least 50 wt %acrylic or methacrylic monomer units and a Tg of −40° C. to 0° C., afiller and a white pigment, wherein the pigment volume concentration ofthe filler plus white pigment is 55% to 90% by volume of total solids.3. The waterproofing membrane according to claim 1 wherein the inorganicfiller is selected from the group consisting of calcium carbonate,silica, diatomaceous earth, barites, magnesium silicates, talc, clay andalumina trihydrate, and wherein the white pigment is selected from thegroup consisting of titanium dioxide, antimony oxide, zinc sulfide, andzinc oxide.
 4. The waterproofing membrane according to claim 1 whereinthe pigment volume concentration of the filler plus white pigment is 60%to 70% by volume.
 5. The waterproofing membrane according to claim 1additionally comprising a releasable bonding layer on the protectivecoating layer, wherein the releasable bonding layer comprises a watersoluble polymer, an alkali soluble polymer, or a homopolymer orcopolymer of polyvinyl acetate.
 6. The waterproofing membrane accordingto claim 5 wherein the releasable bonding layer comprises a polymerselected from the group consisting of polyvinyl alcohol (PVOH),polyethylene oxide (PEO), water soluble cellulosic polymers includinghydroxypropyl methyl cellulose and hydroxyethyl cellulose, hydrolyzedmaleic anhydride polymers and copolymers, polyvinylpyrrolidone,sulfonated polystyrene, polysulfoethyl acrylate,poly(2-hydroxyethylacrylate), polyacrylamide, poly(acrylic acid) andalkali metal salts thereof, natural or synthetically modifiedpolysaccharides, proteins, alginates, xanthan gums, and guar gums,styrene maleic anhydride copolymers, copolymers of acrylic acid andstyrene and/or alpha-methyl styrene, hydroxypropyl methylcelluloseacetate succinate, copolymers of methacrylic acid andmethylmethacrylate, acrylic acid-ethyl acrylate-methyl methacrylatecopolymer, a copolymer of ethyl acrylate, methylmethacrylate, andacrylic acid, rosin acid, and homopolymers or copolymers of polyvinylacetate.
 7. The waterproofing membrane according to claim 5 wherein thereleasable bonding layer comprises a homopolymer of polyvinyl acetate.8. The waterproofing membrane according to claim 5 wherein thereleasable bonding layer additionally comprises nanoscale silica in anamount of 30% to 70% by volume of the silica plus polymer.
 9. Thewaterproofing membrane according to claim 8 wherein the releasablebonding layer has a coating weight of 1 g/m² to 15 g/m².
 10. Thewaterproofing membrane according to claim 9 wherein the nanoscale silicahas a particle size of 5 nm to 30 nm.
 11. The waterproofing membraneaccording to claim 1 additionally comprising a releasable bonding layeron the protective coating layer, wherein the releasable bonding layercomprises nanoscale silica and a binder.
 12. The waterproofing membraneaccording to claim 11 wherein the binder comprises a homopolymer ofpolyvinyl acetate, and wherein the nanoscale silica is present in anamount of 30% to 70% by volume of the silica and binder.
 13. Thewaterproofing membrane according to claim 1 wherein the protectivecoating layer has a textured surface.
 14. A waterproofing membrane inthe form of a sheet-like laminate comprising a carrier sheet, a pressuresensitive adhesive layer on one surface of the carrier sheet, aprotective coating layer on the adhesive layer, and a releasable bondinglayer on the protective coating layer, wherein the releasable bondinglayer comprises nanoscale silica and a binder, wherein the nanoscalesilica is present in an amount of 30% to 70% by volume of the silica andbinder, and wherein the releasable bonding layer has a coating weight of1 g/m² to 15 g/m².
 15. The waterproofing membrane according to claim 14wherein the binder comprises a water soluble polymer, an alkali solublepolymer, or a homopolymer or copolymer of polyvinyl acetate.
 16. Thewaterproofing membrane according to claim 15 wherein the bindercomprises a polymer selected from the group consisting of polyvinylalcohol (PVOH), polyethylene oxide (PEO), water soluble cellulosicpolymers including hydroxypropyl methyl cellulose and hydroxyethylcellulose, hydrolyzed maleic anhydride polymers and copolymers,polyvinylpyrrolidone, sulfonated polystyrene, polysulfoethyl acrylate,poly(2-hydroxyethylacrylate), polyacrylamide, poly(acrylic acid) andalkali metal salts thereof, natural or synthetically modifiedpolysaccharides, proteins, alginates, xanthan gums, and guar gums,styrene maleic anhydride copolymers, copolymers of acrylic acid andstyrene and/or alpha-methyl styrene, hydroxypropyl methylcelluloseacetate succinate, copolymers of methacrylic acid andmethylmethacrylate, acrylic acid-ethyl acrylate-methyl methacrylatecopolymer, a copolymer of ethyl acrylate, methylmethacrylate, andacrylic acid, rosin acid, and homopolymers or copolymers of polyvinylacetate.
 17. The waterproofing membrane according to claim 15 whereinthe binder comprises a homopolymer of polyvinyl acetate.
 18. Thewaterproofing membrane according to claim 17 wherein the nanoscalesilica has a particle size of 5 nm to 30 nm.
 19. The waterproofingmembrane according to claim 15 wherein the protective coating layercomprises an acrylic or methacrylic polymer having at least 50 wt %acrylic or methacrylic monomer units.
 20. The waterproofing membraneaccording to claim 15 wherein the protective coating layer has apenetration ≦20 dmm (ASTM D5), and a reflectivity ≧55%, measured by areflectometer perpendicular to a surface illuminated at a 45° angle, andwherein the protective coating layer comprises an acrylic or methacrylicpolymer having at least 50 wt % acrylic or methacrylic monomer units anda Tg of −40° C. to 0° C., a filler and a white pigment, wherein thepigment volume concentration of the filler plus white pigment is 55% to90% by volume.
 21. The waterproofing membrane according to claim 15wherein the protective coating layer has a textured surface.
 22. Amethod of waterproofing a concrete structure comprising applying awaterproofing membrane in accordance with claim 1 to a buildingsubstrate or concrete form with the protective coating layer of saidmembrane facing the area into which the concrete will be cast, andcasting concrete such that it contacts the protective coating layer ofthe membrane.